Capacitive sensors are used, for example, as capacitive pressure sensors to measure pressure or as capacitive humidity or moisture sensors to measure humidity or moisture but can also be employed to measure the pressure changes caused by Karman vortex street in vortex flowmeters.
U.S. Pat. No. 5,257,210 describes comprehensively how erroneous components of the measurand can be linearized and compensated for. The principle of this linearization and compensation consists of first deriving from the measurand an electric signal, hereinafter referred to as "sensor signal", and only then impressing on the sensor signal a disturbance signal generated by a further sensor per disturbance variable.
In the embodiments of U.S. Pat. No. 5,257,210 relating to capacitive pressure sensors with a measuring capacitor and a reference capacitor, therefore, the disturbance signals are processed, together with the sensor signals, only in stages following the measuring and reference capacitors by switched-capacitor quantized charge transport. To accomplish this, several functional units are provided which are controlled by clock signals having a period equal to forty times that of a basic clock signal. The circuitry of the functional units is rather complicated, so that the total number of components required for them is considerable. Also, those forty basic clock signal periods must have elapsed before the prior art arrangement has generated the compensated and desired smoothed output signal.